Portion of a bed



FIG. 1 is a perspective view of a portion of a bed showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof; and,

FIG. 4 is a left-side view thereof, the right-side view being a mirror-image thereof.

The short broken line showing in the drawings is illustrative and forms no part of the claimed design. The dash-dot broken line showing on the headboard represents boundaries of the claimed design and forms no part of the claimed design. 

The ornamental design for a portion of a bed, as shown and described. 